PERFORATOR ASSEMBLY FOR REWINDER OF SHEET MATERIAL

摘要

Perforator assembly (2) for rewinder machines (1) of sheet material, particularly paper, comprising a perforator cylinder (5) rotating around its own axis, provided on its shell with an even number plurality of blades (31) with continuous cutting edge and helical profile, and a normally fixed counter-cylinder (3) having a rectilinear counter-blade (33) with discontinuous cutting edge, such that during rotation of the perforator cylinder (31) there is a continuous punctiform contact between a blade (31) and the counter-blade (33), determining, on a web material (N) passing between the cylinders (5) and (3), transverse perforation lines at regular intervals dependent on the distance between the blades (31) and on the peripheral speed of the perforator cylinder (5) with respect to the feed rate of the web (N) wherein said blades (31) are mounted on the perforator cylinder (5) so as to be able to be brought from a work position in which they come into contact with said counter-blade (33) to produce the perforation of the web (N) to a rest position distanced from the counter-blade (33) to make the web (N) pass freely.